1. Technical Field
The disclosure generally relates to heat sinks, and particularly to a heat sink having a plurality of interlocked fins that are material saving.
2. Description of Related Art
It is well known that electronic components such as central processing units (CPUs) of computers generate a large amount of heat during operation. In order to remove the heat generated by the CPU quickly, a cooling device such as a heat sink is generally used to dissipate the heat. Typically, the heat sink includes a plurality of metal fins which are disposed in parallel with each other.
In earlier day, a heat sink generally includes a flat base and a plurality of metal fins integrally formed with and extending upwardly from the base. The heat sink is typically an aluminum heat sink and is manufactured by an extrusion process. It is well known by those skilled in the art that, if the heat sink is integrally formed by an extrusion process, the metal fins of the heat sink cannot be made to have a large enough surface area available for heat dissipation. For example, a height of each of the metal fins and a spacing between every two of the metal fins are seriously restricted in the extrusion process.
Presently, most of the heat sinks are not an integral one. The metal fins of the heat sink are manufactured separately and then combined with each other by interlocking units formed between them. FIG. 1 shows a conventional heat sink. The heat sink includes a plurality of metal fins 90 stacked with each other. Each metal fin 90 includes a main plate 91 and a pair of flanges 92 extending perpendicularly from upper and lower sides of the main plate 91. The metal fin 90 has four interlocking units 93 formed at four corners of the metal fin 90, respectively. Each interlocking unit 93 includes an ear 95 and a projection 94. The ear 95 extends forwardly from a front edge of the flange 92 towards a front adjacent fin 90. The projection 94 extends upwardly from a top edge of the main plate 91. A hole 96 is defined in the flange 92 between the ear 95 and the projection 94. In assembly, the metal fins 90 are arranged parallel to each other. The ear 95 of a rear metal fin 90 is received in a corresponding hole 96 of a neighboring front metal fin 90, and the projection 94 of the neighboring front metal fin 90 abuts an inner edge of the ear 95 of the rear metal fin 90. Thus, the fins 90 are locked together.
FIG. 2 shows a metal sheet used for manufacturing the metal fin 90 of the heat sink of FIG. 1. A region between each two adjacent broken lines 98 functions as a boundary of the main plate 91 and the flange 92. Because the ears 95 extend outwardly from an outer edge of each flange 92, a leftover material 97 needs to be provided at the outer edge of each flange 92 to form the ears 95, thereby increasing an area of a metal sheet used for manufacturing the metal fin 90. For instance, when the metal fin 90 has a size of 1709.5 mm2 (square millimeter) (length=131.5 mm; width=13 mm, i.e., a width of the main plate 91 plus the two flanges 92 before the flanges 92 are bent relative to the main plate 91), a metal sheet used for forming the metal fin 90 needs a larger size of 2380.15 mm2 (length=131.5 mm; width=18.1 mm, i.e., a width of the main plate 91 and the two flanges 92 plus the two leftover materials 97). Therefore, the metal sheet for forming the metal fin 90 of the conventional heat sink needs a large area and the leftover materials form waste of material.
For the foregoing reasons, therefore, there is a need in the art for heat sink which overcomes the limitations described.